Automatic damper



Patented Sept. 21, 1926.

rar-enr l CARL MIEHLKE, orrrrnn'rronn, 'wIscoN'sIN AUTOMATIC DAIVIPER.

Applicational'ea November 19, 1925.,- seria1N-o. 70,019. Y

" VThis invention relates to automatic damp,V

ers or draft regulators. Y r' Objects of this invention are to provide an automatic damper which will'control the,

.draft for a furnace, for instance, and maintain the draft at any fixed or desired amount irrespective of fluctuations due to atmospheric conditionsl Further yobjects are to provide a device which, although substantially instantly re-.

sponsive, 'nevertheless does not produce a sudden or violent variation in the draft, but produces a more uniform or gradual variation. such as is needed in furnaces.A

An embodiment of the invention is shown v in the accompanying drawings, in which Figure 1 is a plan view of the device. ,Figure 2 is a sectional elevation thereof.

Fi` ure 3 is a detail of theknife edge pivot for t e damper. y

Figure 4 is a further detailof'the connection between the balancing lever and the valve or disk.

The damper comprises a cylindrical casing 1 into which a pair of pipes 2 and 3 open. These pipes may be connected to the furnace and the chimney, respectively, though theA order of connection may be reversed, as the device will work equally well for either connections.' Thev cylindrical member is closed eXceptfor the relatively large opening 4 through its top wall. Be-

low this opening'a valve or disk 5 is Vposi-y tioned. This valve or disk is preferably made of thin sheet met-al -so as to keep the weight down and is centrally apertured andV receives the bearing member 6 which is shown in greater detail in Figure 4. This bearing member has a relatively large and elongated aperture 7 formed therein Vand provided with a rounded top.l The point 8 of a rod or lever 9 fits loosely into this aperture and provides a pivot bearing for the disk. This rod or lever 9 is bent angularly to provide passes upwardly through the casing 1. Tt is provided with a pair of knife edges 11 formed, as illustrated in Figure, from an integral portion of the lever. These knife edges seat4 in slots formed in hardened bearing blocks 12,V The lever continues ,outwardly and is provided with an outwardly projecting arm 13 upon which a weight 14 is adjustably mounted, preferably being located in adjusted position by means of a set screw 15.

an upright portion 10 whichk From the description thus fari given, it isapparent that when the Vdraft tor suction eXceeds a predetermined amount the disk or valve 5 will be drawn downwardly .to relieve this suction and restore it to a predetermined lvalue due to the setting of the weight 14.

However, if the apparatus consisted only of these parts, the alteration or change from f an intense suction to a lesser suction would be too violent and would upset the operation of the furnace'and also produce 'chattering of the device.A j

In order to make this changemore gradual and uniform, a novel mechanism is asso-- ciated with the diskf and controlled by the position of the disk. This mechanism 'comprises a `pin or shaft 16'which slidably passes through bearings carried by the outer end of an arm 17 (see FigureQ). It is preferably provided with. a `collar 18 adjacent -its upper end to prevent thel shaft from sliding completely out of the bearings. The lower end ofthe shaft carries a fan 19, as shown particular-ly in Figures 1 and 2. This fanV is Yof slightly `less diameter than the opening 4 an-d is normally positioned above the openingwhen the device is closed. However, when' the. device opens duefto excess suction, the bearingmember 6 movesvdownj wardly withthe disk 5 and allows the shaft 16 to slide downwardly, such shaft resting. upon the bearing member 6. This positions n the fan 19 substantiallywithin the opening 4. The fan does not immediately come up to full speed due to the inrushing air, but' a certain interval of time Velapsesbefore it attains this speed. Consequentlyet-he flow of air is at first retarded and israllowed to gradually increase as the fan ycomes up vto speed and offers less and lessfresistance to p the inwardly flowing air.

Further, the fan preventslthe discharger l of soot or sparks from the device, for if the suction should suddenly cease dueto variation in wind pressure, for instance, or to' other causes, the air would not be imme` diately forced out of the opening `4 as the spinning fan would prevent such outwardk passage until the disk 5 had .time to close..

Thus, it willbe seen that the fau serves a novel purpose and performs this double function of making a more gradual change from an excessive suctionto a gradual suction than could be obtained merely by the valve or disk 5, and also prevents the egress j of sparks or soot.

' may be setso'that it responds to any desired Vcondition.

Although the invention has been described in considerable detail` it is to he understood that the invention may he variously embodied and the scope of the invention is to be determined as claimed,

Ipclaim: ,i *n Y An automatic damper comprising a casing having an inlet pipe and an outlet pipe and having an opening in its upper side,4 a Vdisk positioned below said opening and normally closing such opening7 means'normally tending to hold said disk in lclosed position,'and a' fan positioned alooveV said disk and adapted to move downwardly into said opening v When said disk is displaced.

In testimony thatI vclaim the foregoing'` I have hereunto set my hand at Hartford,

in the county of VVa'shington and -Satate of "Wisconsin CARL MIEHLKE. Y Y 

